The ticking is gone! About a month ago I finally gave Vinnie a call and drove the car from Manchester to New Milford to the Zemergency room for a check up. My oil spray bar was broken causing more than normal wear and tear on the cam and rockers, This would have been a perfect time for a performance cam install right!! I thought so too but too many things needed attention so a used cam and set of rockers were installed, and what a huge difference. The 260z now sounds like a real car and not an angry sewwing machine. The timing chain was also in the wrong place and the carbs where set too rich I wonder who did that? A few other things got looked at and since then I have put a few hundred miles on the odometer! Vinnie did great work for a reasonable price and I couldnt be happier with his work. He said i needed a new clutch soon and he was right, under full acceleration it has started to slip, so until i can get it back to him slow and cool i will go which is fine because many other things need more attention too, like wandering steering on the highway and rock hard brakes

the brakes a very hard, also when at a stop the idle stays around 8-900 rpm but if im pressing the brake it climbs to 12-1300 I cant remember exactly where it ends up. this leads me to think its the brake booster and a vacuum issue.

This is what I found wrong with mine when I got it back:In the brake booster vacuum line (btwn the manifold and the booster), the previous owner had reversed the One-Way Valve and put the hoses back over it. That prevented access to manifold vacuum so the power assisted brakes had no assist at all except both my feet. I reversed the valve and the first time I pressed the pedal it about threw me thru the windscreen.

You might not even know that valve exists; it hides completely on your firewall, under a hold down clamp. The hose btwn the booster and the manifold is two-piece and the valve lives at the junction, but the clamp holding the hoses to the firewall conceals the junction.

The valve looks identical on both ends so novices often install it backwards, but one end is slightly smaller than the other. It only allows air to flow in one direction (hence the name) so you can blow thru it to determine which way the air flows. Try reversing it then try your brakes again (carefully) .

This is what I found wrong with mine when I got it back:In the brake booster vacuum line (btwn the manifold and the booster), the previous owner had reversed the One-Way Valve and put the hoses back over it. That prevented access to manifold vacuum so the power assisted brakes had no assist at all except both my feet. I reversed the valve and the first time I pressed the pedal it about threw me thru the windscreen.

You might not even know that valve exists; it hides completely on your firewall, under a hold down clamp. The hose btwn the booster and the manifold is two-piece and the valve lives at the junction, but the clamp holding the hoses to the firewall conceals the junction.

The valve looks identical on both ends so novices often install it backwards, but one end is slightly smaller than the other. It only allows air to flow in one direction (hence the name) so you can blow thru it to determine which way the air flows. Try reversing it then try your brakes again (carefully) .

Learn me something, please. Which way should the vacuum (suction) be going? Or, when you blow through it, should you be able to blow from the manifold toward the booster or vice a versa? Thank you oh mighty wizard(s).

Manifold vacuum will pull air thru the brake master into the engine when you step on the brake pedal. The pedal opens a valve inside the booster, allowing atmospheric air pressure [about 14 pounds per square inch] to press against one side of the diaphragm, while opening the opposite side of the diaphragm to manifold vacuum, which varies but is much lower than atmospheric pressure. The result is the flexible diaphragm bowing hard in the direction of the vacuum side.

Because it's attached to the brake master cylinder rod, the diaphragm helps push the brake rod for you. The larger the diaphragm, the more "push" it can give (more square inches to apply 14lbs per square inch to), so the larger the diaphragm is, the harder the brake booster works for you.

The lightweight early 240Z had a brake booster diaphragm the size of a saucer; the later, heavier cars have dinner plate diaphragms.

Eventually the booster diaphragm ruptures or tears, allowing atmospheric pressure to simply leak thru the booster into the manifold, which drops the manifold vacuum and makes the car stumble and idle poorly. When you step on the brake the valve opens and allows even more air to flood into the manifold, dropping vacuum lower than the engine requires to run, and it stalls.

The one-way valve only opens (allows airflow) to allow air to flow thru it into the manifold when you press on the brake; it then closes to allow the manifold vacuum to remain strong. If it's reversed, no vacuum is applied to the vacuum side of the booster diaphragm and so it cannot help you activate the brakes. You essentially have non-power brakes until you install the valve properly.

Here's an example of the valve [sometimes called a non-return valve or a check valve]. It's the silver thing held under the dash clamp. Vacuum hoses slip onto either end, and the dash clamp covers the fat part of the valve, so unless you know it's there, you might miss it altogether.

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